Upgrade libvips dependency to v8.5.4, plus other bumps

lib/input.js

@@ -1,6 +1,5 @@
 'use strict';
 
-const util = require('util');
 const color = require('color');
 const is = require('./is');
 const sharp = require('../build/Release/sharp.node');
@@ -143,7 +142,7 @@ function clone () {
   const that = this;
   // Clone existing options
   const clone = this.constructor.call();
-  util._extend(clone.options, this.options);
+  clone.options = Object.assign({}, this.options);
   // Pass 'finish' event to clone for Stream-based input
   this.on('finish', function () {
     // Clone inherits input data